refactor: redesign planos interface with design system patterns

- Create CreatePlanModal component with Headless UI Dialog
- Implement dark mode support throughout plans UI
- Update plans/page.tsx with professional card layout
- Update plans/[id]/page.tsx with consistent styling
- Add proper spacing, typography, and color consistency
- Implement smooth animations and transitions
- Add success/error message feedback
- Improve form UX with better input styling

backend/internal/repository/subscription_repository.go

@@ -0,0 +1,203 @@
+package repository
+
+import (
+	"database/sql"
+	"time"
+
+	"aggios-app/backend/internal/domain"
+
+	"github.com/google/uuid"
+)
+
+// SubscriptionRepository handles database operations for subscriptions
+type SubscriptionRepository struct {
+	db *sql.DB
+}
+
+// NewSubscriptionRepository creates a new subscription repository
+func NewSubscriptionRepository(db *sql.DB) *SubscriptionRepository {
+	return &SubscriptionRepository{db: db}
+}
+
+// Create creates a new subscription
+func (r *SubscriptionRepository) Create(subscription *domain.Subscription) error {
+	query := `
+		INSERT INTO agency_subscriptions (id, agency_id, plan_id, billing_type, current_users, status, start_date, renewal_date, created_at, updated_at)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)
+		RETURNING id, created_at, updated_at
+	`
+
+	now := time.Now()
+	subscription.ID = uuid.New()
+	subscription.CreatedAt = now
+	subscription.UpdatedAt = now
+	subscription.StartDate = now
+
+	// Set renewal date based on billing type
+	if subscription.BillingType == "annual" {
+		subscription.RenewalDate = now.AddDate(1, 0, 0)
+	} else {
+		subscription.RenewalDate = now.AddDate(0, 1, 0)
+	}
+
+	return r.db.QueryRow(
+		query,
+		subscription.ID,
+		subscription.AgencyID,
+		subscription.PlanID,
+		subscription.BillingType,
+		subscription.CurrentUsers,
+		subscription.Status,
+		subscription.StartDate,
+		subscription.RenewalDate,
+		subscription.CreatedAt,
+		subscription.UpdatedAt,
+	).Scan(&subscription.ID, &subscription.CreatedAt, &subscription.UpdatedAt)
+}
+
+// GetByID retrieves a subscription by ID
+func (r *SubscriptionRepository) GetByID(id uuid.UUID) (*domain.Subscription, error) {
+	query := `
+		SELECT id, agency_id, plan_id, billing_type, current_users, status, start_date, renewal_date, created_at, updated_at
+		FROM agency_subscriptions
+		WHERE id = $1
+	`
+
+	subscription := &domain.Subscription{}
+	err := r.db.QueryRow(query, id).Scan(
+		&subscription.ID,
+		&subscription.AgencyID,
+		&subscription.PlanID,
+		&subscription.BillingType,
+		&subscription.CurrentUsers,
+		&subscription.Status,
+		&subscription.StartDate,
+		&subscription.RenewalDate,
+		&subscription.CreatedAt,
+		&subscription.UpdatedAt,
+	)
+
+	return subscription, err
+}
+
+// GetByAgencyID retrieves a subscription by agency ID
+func (r *SubscriptionRepository) GetByAgencyID(agencyID uuid.UUID) (*domain.Subscription, error) {
+	query := `
+		SELECT id, agency_id, plan_id, billing_type, current_users, status, start_date, renewal_date, created_at, updated_at
+		FROM agency_subscriptions
+		WHERE agency_id = $1 AND status = 'active'
+		LIMIT 1
+	`
+
+	subscription := &domain.Subscription{}
+	err := r.db.QueryRow(query, agencyID).Scan(
+		&subscription.ID,
+		&subscription.AgencyID,
+		&subscription.PlanID,
+		&subscription.BillingType,
+		&subscription.CurrentUsers,
+		&subscription.Status,
+		&subscription.StartDate,
+		&subscription.RenewalDate,
+		&subscription.CreatedAt,
+		&subscription.UpdatedAt,
+	)
+
+	return subscription, err
+}
+
+// ListAll retrieves all subscriptions
+func (r *SubscriptionRepository) ListAll() ([]*domain.Subscription, error) {
+	query := `
+		SELECT id, agency_id, plan_id, billing_type, current_users, status, start_date, renewal_date, created_at, updated_at
+		FROM agency_subscriptions
+		ORDER BY created_at DESC
+	`
+
+	rows, err := r.db.Query(query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var subscriptions []*domain.Subscription
+
+	for rows.Next() {
+		subscription := &domain.Subscription{}
+		err := rows.Scan(
+			&subscription.ID,
+			&subscription.AgencyID,
+			&subscription.PlanID,
+			&subscription.BillingType,
+			&subscription.CurrentUsers,
+			&subscription.Status,
+			&subscription.StartDate,
+			&subscription.RenewalDate,
+			&subscription.CreatedAt,
+			&subscription.UpdatedAt,
+		)
+
+		if err != nil {
+			return nil, err
+		}
+
+		subscriptions = append(subscriptions, subscription)
+	}
+
+	return subscriptions, rows.Err()
+}
+
+// Update updates a subscription
+func (r *SubscriptionRepository) Update(subscription *domain.Subscription) error {
+	query := `
+		UPDATE agency_subscriptions
+		SET plan_id = $2, billing_type = $3, current_users = $4, status = $5, renewal_date = $6, updated_at = $7
+		WHERE id = $1
+		RETURNING updated_at
+	`
+
+	subscription.UpdatedAt = time.Now()
+
+	return r.db.QueryRow(
+		query,
+		subscription.ID,
+		subscription.PlanID,
+		subscription.BillingType,
+		subscription.CurrentUsers,
+		subscription.Status,
+		subscription.RenewalDate,
+		subscription.UpdatedAt,
+	).Scan(&subscription.UpdatedAt)
+}
+
+// Delete deletes a subscription
+func (r *SubscriptionRepository) Delete(id uuid.UUID) error {
+	query := `DELETE FROM agency_subscriptions WHERE id = $1`
+	result, err := r.db.Exec(query, id)
+	if err != nil {
+		return err
+	}
+
+	rowsAffected, err := result.RowsAffected()
+	if err != nil {
+		return err
+	}
+
+	if rowsAffected == 0 {
+		return sql.ErrNoRows
+	}
+
+	return nil
+}
+
+// UpdateUserCount updates the current user count for a subscription
+func (r *SubscriptionRepository) UpdateUserCount(agencyID uuid.UUID, userCount int) error {
+	query := `
+		UPDATE agency_subscriptions
+		SET current_users = $2, updated_at = $3
+		WHERE agency_id = $1 AND status = 'active'
+	`
+
+	_, err := r.db.Exec(query, agencyID, userCount, time.Now())
+	return err
+}